Aerovortex mill

ABSTRACT

The VIASAD/JETIASAD mechanism generates vortices/high speed jet streams in the vicinity behind the rotating wind mill rotor blades, in order to induce acceleration of the air hitting the wind mill rotor blades. The new idea here is the concept of using vortices or high-speed jet streams in order to create suction behind the wind mill rotor blades and eventually increase the speed of the incoming air flow. The consequences of this concept related to the way a wind mill functions, are the following: (1) It lowers the wind mill&#39;s cut-in wind speed, which means that the wind mill starts producing power at lower wind speeds. (2) Increase the wind mill power output for a given wind speed, and thus increase its efficiency. The VIASAD/JETIASAD mechanism renders the use of wind mills for generating electricity, economically viable and technically feasible in areas with low mean annual wind speeds.

Aerovortex Mill: A Wind Mill using a device which generates high-speedair jet streams or vortices behind the rotor blades, inducing theincrease of the free stream velocity of air (Wind) hitting the rotorblades. The vortex generator device is given the name VIASAD whichstands for Vortex Induced Air Speed Amplification Device. The jet-streamgenerator device is given the name JETIASAD which stands for JET streamInduced Air Speed Amplification Device. The Aerovortex Mill using theVIASAD/JETIASAD device, can generate higher power output in regions withlow mean annual wind speeds.

CROSS-REFERENCE TO RELATED APPLICATIONS

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STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

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REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTINGCOMPACT DISC APPENDIX

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BACKGROUND OF INVENTION

Wind constitutes one of the major sources of renewable or “green” energyproduction. Windmills are widely used all over the world in order toharness this power from the wind.

Currently there are two types of windmills: vertical axis and horizontalaxis machines. They both use some kind of propeller which is primarilyused for extracting or converting the Kinetic Energy of the wind intomainly two types of energies: (1) Electrical energy (Power generators)and (2) Potential energy of the water (Water pumps). These propellers orrotors are either drag-based or lift-base devices. The drag-based rotorshave slower rotational speeds than the lift-based devices. Generally thelift-based devices are a lot more efficient than the drag-based devices,and consequently the wind power generators are mostly lift-baseddevices.

A lot of research and development has been done by a number of companiesaround the world in order to improve the efficiency and performance oflift-based windmills. This lead to a number of considerable advances inthis field, primarily focused on the following three areas:

-   -   1. The aerodynamics of the rotor blades. Basically maximize the        Lift-to-Drag ratio of the rotor blades.    -   2. Wind mill yaw control and rotor blade pitch control.    -   3. Improvement of the gear system which amplifies rotation from        the main rotor with the blades to the generator. Lately a        gearless design has been introduced. This advancement drives        down considerably the maintenance costs, since the gear system        is one of the most sensitive parts and wares out the most.

How many advances have been achieved in Windmill technology, even themost advanced and efficient Windmills can only operate in areas withmean annual wind speeds exceeding 4.5 m/s. Only then, they can generateenough useful energy or electricity to justify their extremely highcost. As a result, areas with low mean annual wind speeds (below 4.5m/s), are left with no reliable and efficient enough technology toharness the energy of the wind.

The recommended invention/mechanism, does not radically changes the mostwidely used way of harnessing the wind energy, which is the use ofhorizontal axis lift-based wind turbines. This technology has been indevelopment the last three decades and it has reached very highstandards of efficiency. The recommended invention builds on thisexisting and proven technology and renders it more efficient and hence alot more attractive. Exactly for this reason, from a practical andfinancial point of view, the implementation of the invention becomesvery feasible and economically viable.

BRIEF SUMMARY OF THE INVENTION

The use of a vortex generator device to generate vortices in thevicinity behind the wind mill rotor blades, can render the conventionalwind mill a far more efficient device at low wind speeds. The sameapplies for a mechanism blowing high-speed air jet streams behind thewind mill rotor blades. By using these devices, the wind mill will beable to operate in an environment with winds in the lower speed spectrum(1 m/s<v<5 m/s) and at the same time produce electricity (power)efficiently and cost effectively.

The vortices as well as the jet streams generated by the proposedmechanism or device, in the vicinity behind the wind mill rotor blades,help accelerate the free stream air by lowering the static pressure inthat region and hence inducing a suction effect. As a result, the windmill's output performance is improved.

The vortex generator mechanism is given the name VIASAD which stands for“Vortex Induced Air Speed Amplification Device”. The jet-streamgenerator device is given the name JETIASAD which stands for “JET streamInduced Air Speed Amplification Device”. The Wind Mill carrying theVIASAD/JETIASAD device, is called: “Aerovortex Mill”.

In simple terms, the concept mechanism will especially benefit areaswith low mean annual wind speeds. The production of electricity at lowwind speeds by an Aerovortex Mill, will be comparable to that producedat a lot higher wind speeds with current wind mill technology not usingthe VIASAD/JETIASAD device.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1: Swimming/Propulsion of a human swimmer in water. The feet strokeup and down in the water generating ‘barrel’ like trailing vortices.

FIG. 2: Fish/Shark swimming. The periodical (left/right) movement of theshark's caudal fin shreds trailing vortices. A jet stream flows inbetween the trailing vortices with a direction opposite to the directionof travel of the shark.

FIG. 3: Insect flapping flight. Shredding of vortices which induces ajet stream on top of the flapping wings.

FIG. 4: 3D view of a type1 VIASAD/JETIASAD Device: Two convergent windtunnels (Contraction), each with a single exhaust nozzle behind therotor of a wind mill.

FIG. 5: 3D view of a type1 VIASAD/JETIASAD Device with two convergentwind tunnels. Generated vortices, one from each exhaust nozzle and witha direction of flow perpendicular to the plane of rotation of the rotor.A horizontal flap controls the vortices flow.

FIG. 6: 2D side view of a type1 VIASAD/JETIASAD Device with twoconvergent wind tunnels: A generated vortex flows from a single exhaustnozzle.

FIG. 7: 3D view of a type2 VIASAD/JETIASAD Device with four convergentwind tunnels: Accelerated air flow through the nozzles is ejected fromfour exhaust nozzles behind the rotor of a wind mill.

FIG. 8: 2D side view of a type2 VIASAD/JETIASAD Device with fourconvergent wind tunnels: Two generated vortices flow out of doubleexhaust nozzles, one on each side of the wind mill (Right/Left sides).

FIG. 9: 3D view of a VIASAD/JETIASAD Device with two convergent windtunnels: A casing or walls isolate the space behind the wind mill rotor.

FIG. 10: 3D view of a type3 VIASAD/JETIASAD Device with two convergentwind tunnels, one on each side of the wind mill rotor. The exhaustnozzle of the first wind tunnel blows air behind the top half of therotor and the exhaust nozzle of the second wind tunnel blows air behindthe bottom half of the rotor. Generated vortices flow along a directionparallel to the plane of rotor rotation.

FIG. 11A: 2D TOP view of a type3 VIASAD/JETIASAD Device with twoconvergent wind tunnels on each side of the wind mill rotor.

FIG. 11B: 2D FRONT view of a type3 VIASAD/JETIASAD Device with twoconvergent wind tunnels on each side of the wind mill rotor.

FIG. 11C: 2D SIDE view of a type3 VIASAD/JETIASAD Device with twoconvergent wind tunnels on each side of the wind mill rotor.

FIG. 12: 3D view of a type4 VIASAD/JETIASAD Device with its wind tunnelsconverging to a unified exhaust nozzle behind the wind mill rotor. Theflow direction of the generated vortices makes an angle with the rotorplane.

FIG. 13A: 2D TOP view of a type4 VIASAD/JETIASAD Device.

FIG. 13B: 2D FRONT view of a type4 VIASAD/JETIASAD Device.

FIG. 13C: 2D SIDE view of a type4 VIASAD/JETIASAD Device.

FIG. 14: 3D view of a type5 VIASAD/JETIASAD Device with two convergentwind tunnels, one on each side of the wind mill rotor. The exhaustnozzle of the first wind tunnel blows air behind the top half of therotor and the exhaust nozzle of the second wind tunnel blows air behindthe bottom half of the rotor. Double counter-rotating vortices areexiting each exhaust nozzle of the convergent wind tunnels.

FIG. 15: 3D view of a type6 VIASAD/JETIASAD Device with its two windtunnels converging to “scissors” like exhaust nozzles.

FIG. 16: 3D view of a type6 VIASAD/JETIASAD Device with one of its twoconverging wind tunnels. The generated counter-rotating vortices inducea jet stream of air through the “scissors” like exhaust nozzle.

FIG. 17: 2D TOP view of a type7 VIASAD/JETIASAD Device. Swept-forwardwings at an angle of attach to the incoming wind generate vortices attheir roots, behind the wind mill rotor.

FIG. 18: 2D SIDE view of a type7 VIASAD/JETIASAD Device withswept-forward wings at an angle of attach to the incoming wind.

DETAILED DESCRIPTION OF THE INVENTION

The paragraphs 0012 to 0019 that follow, provide necessary backgroundinformation related to the invention in order to be fully understood.This introductory information naturally leads to a detailed descriptionof the invention.

The Power Available in the Wind:

The following formula gives the total power contained in the Wind of acertain speed and through a given cross-sectional area.P _(W)=(½)*(Density)*A*V ³

-   P_(W)=Power available in the wind (W)-   Density=Density of air (Kg/m³).-   A=Swept rotor area (m²)-   V=Wind speed (m/s)    Power Produced by a Wind Mill:

The following formula calculates the power output from a wind mill giventhe available power in the wind.P _(M) =C _(P) *P _(W)

-   P_(M)=Power available from the wind machine (W)-   C_(P)=Coefficient of performance of the wind mill    C_(P) depends on a number of factors like the type of the wind mill    (drag-based or lift-based) and the rotor used. The drag-based    devices achieve their maximum performance efficiency at low wind    speeds and hence low tip-speed ratio. On the other hand, the    lift-based devices achieve their maximum performance efficiency at    high tip-speed ratios. However, it is very important to note here    that the maximum performance output achieved by the lift-based    devices is a lot higher than the corresponding performance output    given out by the drag-based devices.

According to the Betz Law (Known as Betz limit) there is a maximum valueof C_(P) which is equal to 59.3%. In practice, though, real wind rotorshave maximum C_(P) values in the range of 10%-40%.

Based on the formula of paragraph 0012, the Power which can be harnessedfrom the wind by propellers is heavily dependent on the wind speed(speed cubed).

The Wind as an Energy Resource

Large areas of the world appear to have mean annual windspeeds below 3m/s, and are unsuitable for wind power systems, and almost equally largeareas have windspeeds in the intermediate range of 3-4.5 m/s where windpower may or may not be an option. In these areas, drag-based windmachines are the most efficient but rarely are used for power generationbecause of their low rotational speeds.

Those areas with mean annual windspeeds exceeding 4.5 m/s are the mosteconomically competitive for power generation. In these areas lift-baseddevices are being used, because they are usually more efficient thandrag-based devices, even though at extremely high wind speeds theirefficiency considerably drops.

In summary, the most efficient current technology based onlift-generating rotor wind mills, can operate in areas with mean annualwind speeds exceeding 4.5 m/s and generate enough useful energy orelectricity to justify their extremely high cost. On the other hand,areas with low mean annual wind speeds (below 4.5 m/s), are left with noreliable and efficient enough technology to harness the energy of thewind.

The Inspiration

The source of inspiration for the recommended concept device(VIASAD/JETIASAD), consists of specific lessons from nature which can besummarized as follows: The Hydrodynamic mechanisms of Aquatic Locomotionused by fishes to propel their way through fluids and the Flightpropulsion mechanisms used by birds and insects moving through Air.

1. Aquatic Locomotion

The Momentum-Impulse Couple of Vortex REAR DRIVEN Bodies:

The rear body parts (feet, caudal fin) can both (A) accelerate thevortex flow generated by the body moving through the water and/or (B)generate vortices.

-   -   A. The vortex flow generated by the body of the fish is allowed        to expand laterally and eventually it is beaten by the caudal        fin. This effectively restricts its path and hence the vortex        flow is being accelerated.    -   B. The rear body parts preform the aquatic surroundings by        applying some work on the water, which in turn stores this        energy. The preformed water masses flow into the zone of the        underpressure creating a rolling vortex (Ungerechts et al). Due        to the high geometrical organization, vortex ‘carry a high        amount of momentum in relation to the energy spent for their        production’ (Lighthill, 1969). This generated trailing vortex        induces a velocity field which is influencing the flow in front        of the moving body.

1.1 Human Swimmer

-   -   The feet strokes up and down in the water generate ‘barrel’ like        trailing vortices. It looks as if the human body is translating        through the water between rollers. See FIG. 1.

1.2 Shark

-   -   The periodical (left/right) movement of the shark's caudal fin        shreds vortices on each side which are rotating in an opposite        sense (Blickman, 1992). Due to the lasting rotation of the        generated vortices, a jet stream is produced. This jet stream        flows in between the trailing vortices and with a direction        opposite to the direction of travel of the shark (backwards).        The thrusting impulse responsible for pushing the shark forwards        is a reaction to this jet stream (similar to the jet stream        behind modern aircraft). See FIG. 2.        2. Flight Propulsion

2.1 Insect Flapping Flight

-   -   The very slow velocities by which insects fly in the air and        hence the low Reynolds numbers associated with these velocities,        do not justify the lift generated on their wings in order to        keep them airborne. For this reason, insects use flapping along        with rotational movement of their wings, in order to increase        the airflow in the vicinity of each of their flapping wings and        in this way generate the required lift so that they are able to        fly. The way this is achieved is by generating wing leading-edge        vortices (LEV) which in turn produce a jet stream on top of the        wing. See FIG. 3.        The Invention

A device which increases the speed of Air Flow (Wind) in the vicinity ofthe wind mill rotor blades. Based on the formulas given in paragraphs0012 and 0013 above, the power output of a wind mill is proportional tothe 3^(rd) Power of the speed of the air stream hitting the wind millrotor blades. Consequently, by increasing the speed of the air seen bythe rotor blades, the power output will surpass the level correspondingto the free stream air speed.

The proposed device generates a high-speed jet stream or a system ofvortices behind the wind mill rotor blades (downstream). These vorticeslower the static pressure in the region where they are generated andhence they are inducing a suction effect. Also, due to the highgeometrical organization, these vortices carry a high amount ofmomentum, which helps accelerate the free stream air hitting the windmill rotor blades (upstream). This is the reason I call this device:VIASAD, which stands for “Vortex Induced Air Speed AmplificationDevice”. The version of this device which blows air jet streams behindthe rotor blades, is called JETIASAD: “JET stream Induced Air SpeedAmplification Device”.

The Wind Mill operating with the help of the VIASAD/JETIASAD device, Icall it an “Aerovortex Mill”.

The mechanism described above, will render the wind mill a far moreefficient device at low wind speeds. It will be able to operate in anenvironment with winds in the lower speed spectrum (1 m/s<v<5 m/s) andat the same time produce electricity (power) efficiently and costeffectively.

In simple terms, the concept device will especially benefit areas withlow mean annual wind speeds. The production of electricity at low windspeeds by an Aerovortex Mill, will be comparable to that produced at alot higher wind speeds with current wind mill technology not using theVIASAD/JETIASAD device.

Specification:

The VIASAD/JETIASAD device helps increase the speed of air flow hittingthe wind mill rotor blades by inducing suction in the vicinity behindthe rotor blades, and it is based on the following (A)Functionalprinciples and (B)Design variations:

A. Functional Principles:

The principles described below, provide valuable insight into thefunctionality of the VIASAD/JETIASAD device. They can be very helpful inbuilding and operating the device. Essentially, the VIASAD/JETIASADdevice makes use of the Wind in a number of steps/stages as describedbelow:

-   -   (1) Use of a contraction or an open-circuit wind tunnel in order        to accelerate a large mass of incoming free stream air flow.    -   (2) Vortex generators are positioned in the incoming air flow        which is accelerated by the open-circuit wind tunnel.    -   (3) The vortex generator can take various forms and/or        configurations. The following are a few examples:        -   Stationary swept-forward wings.        -   Flapping swept-forward wings.        -   Fins like the shark's caudal fin.        -   Fences positioned vertically or at an angle along the walls            of the open-circuit wind tunnel.    -   (4) Generate a vortex or a number (system) of vortices        positioned in a certain pattern/configuration (VIASAD) or blow        high-speed jet streams (JETIASAD) in the space behind the wind        mill rotor blades.    -   (5) For the generation of the above vortices, make use of air        masses in front and on the side, away from the wind mill rotor        blades circumference. The use of air masses from the undisturbed        free stream away from the buffered area behind the rotor blades,        maximizes the strength of the generated vortex and as a result        it contributes to its increased effectiveness. The same applies        to the generation of air jet streams.    -   (6) Allow some spacing for the generated vortices to expand        laterally (perpendicularly to the direction of flow).    -   (7) Use horizontal and/or vertical flaps or other devices in        order to control/restrict the lateral expansion of the generated        vortices.    -   (8) By restricting the flow path of the generated vortices, the        flow accelerates and consequently the following two effects take        place:        -   The angular momentum of the rotating air masses increases.        -   The static pressure within the accelerated vortices drops.    -   (9) Use walls in order to isolate the region behind the wind        mill rotor blades. Basically, this will only allow incoming air        masses hitting the wind mill rotor blades to be sucked in the        region with the generated vortices.    -   (10) The air masses moving within an imaginary tube with        cross-sectional area described by the disc plane of the rotating        wind mill rotor blades, flow into the underpressure of the        generated rolling vortices or the blowing air jet streams behind        the rotor blades    -   (11) The induced jet stream as a result of the vortex suction        effect (or jet stream suction effect) on the wind, influences        the air flow in front of the wind mill rotor blades by        increasing its incoming speed and ultimately increasing the        energy content of the air masses hitting the rotor blades. This        effectively raises the power output of the wind mill, because it        is proportional to the power (or energy) content of the air flow        masses hitting the wind mill rotor blades.        B. Design Variations:

The following Design variations describe a number of differentconfigurations for the VIASAD device. All recommended designs, aim atgenerating vortices and/or air jet streams behind (or downstream) thewind mill rotor blades, which induce acceleration of the wind hittingthe rotor blades (In the vicinity of the wind mill blades).

(1) Stationary Swept-Forward Wings. (See FIGS. 17-18)

Location/Position:

I. Case1: A single pair of wings is used. The horizontal plane of thewings lies on the same height as the horizontal diameter of the windmill rotor disc.

-   -   II. Case2: Two pairs of wings are used. The horizontal plane of        each pair of wings lies at a height, which makes an offset        (up/down) from the horizontal diameter of the wind mill rotor        disc    -   III. Wing tips are preferably well ahead of the vertical plane        described by the rotating wind mill rotor blades    -   IV. Wing root located behind the wind mill rotor blades.

Functionality:

-   -   I. Spanwise flow of air develops, originating at the wing tips        and moving towards the root of the wings.    -   II. By increasing the angle of attack of the wings to the wind,        a pressure differential is created between the lower and upper        surfaces of the wing. With the low pressure on the lower surface        and the high pressure on the top surface, upwash builds up which        results in air flow rolling up the edge along the root of the        wing.    -   III. The low pressure within the core of each of the pair of        vortices generated along the wing roots, as well as the        impulsive effect of the air masses rotating and moving backwards        in the vortices, result in a suction effect.    -   IV. The suction generated by the vortices, and with the help of        the wind direction, accelerates the air flow from the space in        front of the wind mill rotor blades towards the space behind        them.    -   V. The influence on the air hitting the rotor blades can be        amplified with the use of a containment or walls preventing the        influx of air masses from the sides entering the space where the        vortices are generated.    -   VI. Use flaps or other surfaces in various forms (flat,        cylindrical) in order to restrict the path of the vortices and        hence increase the speed of the rotating air within them.

(2) Flapping Swept-Forward Wings.

Location/Position:

-   -   Similar to Design Variation (1).

Functionality:

-   -   Similar to Design Variation (1). One extra functionality        parameter can be used and/or varied: Flapping frequency.

(3) Fins Like the Shark's Caudal Fin.

(4) Contractions Where Air is Initially Accelerated and EventuallyDiffused in a Rolling Vortex or a High-Speed Jet Stream. TheseContractions are Basically Open Circuit Converging Wind Tunnels. SeeFIGS. 4-16.

Location/Position:

-   -   I. Case1: A single pair of contractions generating a pair of        vortices. The intake sections of the tunnels/contractions are        outside the disc area of the rotating wind mill rotor blades.        They can be placed either ahead or behind the plane of the        rotating wind mill rotor blades.    -   II. Case2: Two pairs of contractions generating two pair of        vortices. The intake sections of the tunnels/contractions are        outside the disc area of the rotating wind mill rotor blades.        They can be placed either ahead or behind the plane of the        rotating wind mill rotor blades.    -   III. The center line of the contractions will be either curved        or straight.    -   IV. The exhaust section of the diffuser of each contraction will        end up behind the wind mill rotor blades.

Functionality:

-   -   I. Free stream air flows into the intake section of the        contraction and eventually is diverted towards the exhaust        section.    -   II. By diverting the air flow from a large cross sectional area        to a small cross sectional area, the air is accelerated        (Bernoulli's Principle).    -   III. The air flow exiting the exhaust section of the diffuser,        hits a vortex generator and rolls into a vortex.    -   IV. The low pressure within the core of the vortices generated,        as well as the impulsive effect of the air masses rotating and        moving backwards in the vortices, result in a suction effect.    -   V. The suction generated by the vortices, and with the help of        the wind direction, accelerates the air flow from the space in        front of the wind mill rotor blades towards the space behind        them.    -   VI. The influence on the air hitting the rotor blades can be        amplified with the use of a converging nozzle placed behind the        rotating wind mill blades and in front of the generated        vortices.

1. A mechanism or device which makes use of the wind and generates asingle high-speed air jet stream or a pattern of multiple high speed airjet streams, of ANY TYPE or configuration, in the vicinity and spacebehind the rotating wind mill rotor blades. The generated high-speed airjet streams induce a suction effect which affects the wind hitting therotor blades: The speed of the wind in the vicinity of the rotatingrotor blades increases, and as a result it considerably improves thepower output of the wind mill. I call this device JETIASAD which standsfor jet stream induced air speed amplification device: The high speedjet streams mentioned above can be generated in ANY WAY and by no meansis limited to the methods described below: Intake nozzles facing thewind, direct the incoming flow through converging ducts or tunnels. Theair as it goes through the contraction is accelerated and eventually itis released (expelled) via an exhaust nozzle. For the airflow to beaccelerated, the intake area (A1) of the duct is a lot larger than theexhaust area (A2). The larger the ratio of the intake area to theexhaust area (A1/A2) the greater it will be the acceleration of the airflow that goes through it.
 2. A mechanism or device which makes use ofthe wind and generates a system or pattern of air vortices, of ANY TYPEor configuration, in the vicinity and space behind the rotating windmill rotor blades. The generated air vortices induce a suction effectwhich affects the wind hitting the rotor blades: The speed of the windin the vicinity of the rotating rotor blades increases, and as a resultit considerably improves the power output of the wind mill. I call thisdevice VIASAD which stands for Vortex Induced Air Speed AmplificationDevice. The vortices mentioned above can be generated in ANY WAY and byno means are limited to the methods described below: (i) Intake nozzlesfacing the wind, direct the incoming flow through converging ducts ortunnels. The air as it goes through the contraction is accelerated andeventually it is released (expelled) via an outgoing or exhaust nozzle.The intake area (A1) of the contraction duct is a lot larger than theexhaust area (A2). The larger the ratio of the intake area to theexhaust area (A1/A2) the greater it will be the acceleration of the airflow that goes through it. The air as it flows through the convergingducts, is guided past vortex generators. These vortex generators cantake the form, but are not limited to, fences or walls or grooves andextrusions or lifting bodies placed at different angles of attack to theair flow. They are located inside the converging duct, but they can alsoextend outside from both the inlet and outlet of the duct. The vortexgenerators can take any geometrical shape that maximizes the performancefor their intended purpose. See FIGS. 4-16. (ii) Swept forward wingsfacing the wind at an angle of attack, generate vortices at their base.The base of the wings is situated behind the wind mill rotor blades andtheir tip extends in the space besides and in front of the rotating windmill rotor blades. See FIGS. 17-18. Moving surfaces or flaps control thedirection of flow of the generated air vortices, and also theyaccelerate the flow by hitting the vortices and hence restricting theirpath. Casing or walls can be constructed to enclose the space behind thewind mill rotor blades, so that only incoming air flow from the front ofthe wind mill rotor blades is being sucked in.